Rheostat



Patented Apr. 5, 1927.

UNITED STATES PATENT OFFICE.

EDWARD B. -NOWOSIELSKI, OF BLOOMFIELD, NEW J'ERSEY, ASSIGNOR TO SPLITDORF ELECTRICALiCOMPANY, OF NEWARK, NEW JERSEY;

RHEOSTAT.

Application filed June 19,

This invention relates to a rheostat to be used in an electrical circuit and in the form shown and described herein the device is member and the parts carried by it may have while .a considerable amount of longitudinal movement without effecting the contact between the convolutions of the wire and the sliding member that engages the wire.

' Another object of my invention is to provide means for connecting the rotary part carrying the sliding contact to one of the rheostat terminals so that this connection will be always ermanent and substantially the same or all movements of. the movable member, whether it travels in a rotary motion or longitudinally.

Another object of my invention is to provide a rheostatwhich is'very simple and compact and easy to manufacture.

' These and other objects will be apparent after a study of the specification taken in connection with the annexed drawing, wherein:

F i ure 1 is an end view of the back of the rheostat with the rotary or contact memher in a position such that the resistance of the rheostat is substantially cut out.

Figure 2 is a view similar to Fig. 1 but with the rheostat in the open position;

Figure 3 is a section on the line 3 3 of Fig. 2, but with the rotary member turned to an intermediate point.

In the drawing, wherein like numbers refer to corresponding parts in the various views, 1 is a cup shaped casing, preferably of non-conducting and heat resisting material. As shown in Fig. 3, the casing 1 is adapted to be attached to a panelboard 2,

shown in dotted lines, in any suitable man 1924. Serial No. 720,886.

ner as by screws passing through inserts 3 and 4, which are preferably moulded integral with the casing 1. The casing at the point where the screws 3 and 4 pass through is preferably reinforced by the bosses 5 on the inside and by the bosses 6 on the outside thereof. Fastened to the bottom of the casing is a pair of terminals 7 and 8. As shown in the drawing these terminals are fastened to the bottom of the casing by means of eyelets which are spun over. Of course it is to 'be understood that they may be attached to the casing in any other satisfactory manner. The terminals 7 and 8 extend outwardly substantially parallel to the side wall of the casing 1 and positioned between the terminals and the wall of the casing is a circular band 9, preferably of insulating material on which the resistance wire 10 is wound, it being-understood that the convolutions of thewire are separated the proper distance.

The form or band 9 has two notches therein corresponding to a similar pair of notches or slots in the casing 1. After the, band 9 has been put in position the outer ends of the terminals 7 and 8 are bent over as is clearly shown in Fig. 3, so as to lie in the slotsfboth in the band 9 and in the casing 1. The terminals, therefore, serve to hold the band 9 in position to prevent rotary and lateral movement with respect to the casing. The outer ends of the terminals may be provided with contact screws 11 or lugs 12 to which connecting wires may be attached. The terminals 7 and 8 are also provided with lugs 13 and 14 respectively, which serve two purposes. To the lug 13 is securely attached'as by soldering, a resilient conducting member 15 preferably shaped in the form of a clock spring. The other end of the spring 15 is attached to a lug 16 on an arm 17 that is fastened to a control rod 18. As will be seen in Fig. 2, the lug 13 further acts as a stop for the arm 17. The arm 17 at its outer end carries acontact spring 19 formed so as to give a positive but easy sliding contact with the inner surface of the wire convolutions carried on the band 9. Vhen the arm 17 is in the position shown in Fig. 2, the end 20 of the spring 19 drops into a depression or recess in the band 9 so as to prevent any jar, vibration or any tension that may come from the spring 15 from moving the spring 19 into contact with the resistance .wire 10.

The control rod 18v is preferably provided with a groove into which asnap ring 21 may be passed so as to hold the control rod from undue longitudinal movement. .The rod 18 is also provided with the usual dial knob 22,

which may be attached thereto in any suitable manner as by set screw 23. One end of the resistance wire is attached to the lug 14 on the terminal 8, and when the control rod is moved from the position shown in Fig. 1, lug 14 acts as a stop for'the spring 19 and the arm- 17. The spring 19 in this 'position makes contact with the surface of the terminal as well as the lug 14 and the rheostat is short-circuited.

The rheostat may be provided, if desired, with a cover 24, which as shown in the drawing can be supported on the outer end of the control rod 18, although it will be observed that the cover may be attached to the casing.

Itwill be seen that there is a direct and positive, yet flexible connection becasing, said unit consisting of a; series of wire convolutions arranged on an arcuately formed member, a control rod, an arm carried by said rod, a resilient member carried by said arm in contact with said wire convolutions, a terminal connected to said wire convolutions, a second terminal and a spirally wound conducting member joiningsaidsecond terminal and'said arm.

2. In a device of the class described, a casing, a resistance unit mounted within the casing, said unit consisting of a series of wire convolutions arranged on an arcuately formed member, a control rod carried by a bearing centrally arranged in the casing, an armon the control rod, a resilient member carried by said arm in contact with said wire convolutions, a terminal connected to one end of said wire, a second terminal and a conductor, spirally arranged around the control rod and bearing, joining said second terminal and said arm.

In a device of the class described, a circular casing, a circular band, having resistance wire wound thereon, mounted with in the casing, a control rod having a central support in the casing, an arm carried by the rod, a current carrying spring member supported by the arm in contact with the wire convolutions on said band, a terminal connected to one end of said wire, a second terminal and a spirally wound conducting member joining said second terminal and said arm.

4. In a device of the class described, a on cular casing, a circular band having resistance wire wound thereon and fitting within the wall of the casing, a pair of terminals fastened to the bottom of the casing and extending outwardly inside said band and having their outer ends bent over said band for holding it within the casing, a centrally mounted control rod, an arm on the control rod, a spring on the arm for contacting with the wireconvolutions on the band, a spirally wound conducting member joining one of said terminals and said arm, said other terminal being connected to one end of the wlre.

5. In a device of the class described, acircular casing of insulating material, a cylindrical band of insulating material having resistance wire -wound thereon and fitting within the wall of the casing, said casing and band having slots in their outer edges, apair of terminals fastened to the bottom of the casing and extending outwardly along the inner surface of said band, said terminals having their outer ends bent over so as to enter the slots in both the bandv and casing, a centrally mounted control rod, an arm on the control rod, a spring on the arm for contacting with the wire convolutions on the band, a spirally wound conducting member joining one of said terminals and said arm, said other terminal being connected to one end of the wire.

6. In a device of the class described, a cup shaped casing, a pair of terminals attached to the bottom of the casing, a resistance unit comprising a band having wire wound thereon, said band being adapted to fit between the terminals and the wall of the casing, said terminals adapted to be bent over the band so as to prevent it from rotating or moving laterally in the casing, a control rod centrally supported in the casing, an arm on the control rod, a spring on the arm for engaging the inner surfaces of the convolutions of wire on the band, a spiral resilient member connecting one terminal and said arm, said other terminal being connected to one end of the resistance wire as described.

7. In a device of the class described, a cup shaped casing, a resistance unit comprising a band having wire woundthereon, said band adapted to fit within the wall of the.

casing, terminals carried by the casing so as to engage and hold the band in place, a con trol rod centrally supported by the casing with means for holding it in position, an

arm on the rod, a spring on the arm extending into sliding engagement with the inner surface of the wire convolutions on the band, a clock spring type of connection between one of said terminals and said arm, the other terminal being connected to one end of the resistance wire as described.

8. In a device of the class described, a cup shaped casing, a resistance unit comprising a band having wire wound thereon, said band adapted to fit within the wall of the casing, terminals carried by the casing so'as to engage and hold the band in place, a control rod centrally supported by the casing with means for holding it in position, an

arm on the rod, a spring on the arm extending into sliding engagement with the inner surface of the Wire convolutions on the band, a clock spring type of connection between one of said terminals and said arm,

the other terminal being connected to one end of the resistance wire, said latter terminal having a lug to act as a stop for said arm and sliding spring contact. v

9. In a device of the class described, a cup shaped casing, a resistance unit comprising a band having wire wound thereon, said band adapted to fit within the wall of the casing, terminals carried by the casing so as to engage and hold the band in place, a control rod centrally supported by the casing with means for holding it in position, an arm 011 the rod, :1 spring on the arm extending into sliding engagement with the inner surface of the wire convolutions on the band, a clock spring type of connection betweenone of said terminals and said arm, the other terminal being connected to one end of the resistance wire, and a cover for closing the end of the cup.

In testimony whereof I afiix my signature.

, EDWARD B, NOVOSIELSKI. 

